Krakipedia lists Evyrsio and Ulthripe as two sorcerers with knowledge of this rune... but I've never run into either.

I did manage to find a pair of Igaesha runes in the playershops some time back, so if you're only interested in illusions progression, those should be enough to get both of us through to Shien. Just shoot me a msg on LNet and we can crank out all 6-7 ranks.